The present invention relates to a device adapted for use on the rear portion of an off-highway or construction vehicle to improve the unrolling of geotextile materials as commonly used in road-beds, landscaping, retention walls, pond-lining, and the like. And, more specifically, the present invention relates to a device that couples to a conveyered material placement vehicle to simultaneously and continuously dispense fabric from a roll as an aggregate is placed on top of the dispensed fabric.
Certain construction techniques for roadbeds, drainage ditches, man-made ponds and other landscaping needs require a cloth or fabric liner layer to be placed on the newly prepared and compacted soil. This cloth or fabric liner typically arrives at the construction site in large roles varying from about 3-feet to about 15-feet in width and (unfurled) having lengths of 300 feet or more for landscape rolls and about 13-feet wide or about 15-feet wide for road-bed fabric rolls, for example.
Fabric rolls used in road construction, landscaping and the like are generally known as geotextiles and are defined by the American Society for Testing and Materials (ASTM) as any permeable textile material used with foundation, soil, rock, earth as an integral part of a construction project, structure, or system and may be synthetic or natural fibers, or both. Geomembranes, also used in similar applications, are continuous membrane-type liners or barriers that have low permeability to control migration of fluid and restrict fluid flow.
In the road construction industry there are essentially four primary uses for geotextiles: separation, drainage, filtration, and reinforcement. However, most often geotextiles are used for stabilizing roads through separation and drainage. Stabilization results from the geotextile acting as a barrier to migration of fines in the subgrade to the base layer (aggregate layer), while simultaneously permitting water to migrate from the base layer to the subgrade or laterally away from the roadbed. Migration of fines is highly undesirable because it weakens the road structure.
Geotextiles are well suited for temporary road construction, particularly in environmentally sensitive areas where a biodegradable woven jute geotextile can be used. Geotextiles are economical for temporary road construction, such as construction roads in isolated areas as are needed to install power grid infrastructure, wind-turbine power generations, or remote logging roads, for example.
Such roads, for example, use a crushed aggregate layer on top of native subgrade material. A geotextile serves as a separation layer between the subgrade and the aggregate, preventing intermixing of the two layers. Intermixing occurs (absent the geotextile layer) from pressure exerted on the road from vehicles, the downward and laterally moving load creates a pump-like affect that draws fines in the subgrade upward, intermixing in the aggregate layer. This affect becomes more dramatic when there is water migration as well.
Thus, proper selection and installation of a suitable geotextile is vitally important in road construction. The installation method for geotextiles (or fabric rolls), as generally known in the art, requires shaping the roadway subgrade, rolling the fabric down the road one lane per roll, and if windy, weight the sides of the unrolled fabric with shovels full of gravel or use spikes or staples to pin the fabric down. Then, dump and spread the gravel or base course material using normal methods with an end dump truck (or belly-dump or side-dump trucks)—but making certain to avoid driving onto the geotextile with any equipment other than rubber-tired vehicles operating over a solid sub-grade in a straight line with no turns and a vehicle speed of no more than seven miles per hour or otherwise risking a puncture or tear, damaging the fabric and making it less suitable for its intended use.
Currently, the tools and methods to unroll these large fabric rolls include a hanger bar coupled to the rear of a vehicle, such as a dump truck (belly, side, or end) or a front-end loader using the bucket to suspend a roller bar and reversing to unroll the material. The hanger bar supports a roll bar adapted to slideably receive a roll of material. Then, several workers unroll a portion of the roll, stand on it, pin it, or manually shovel some aggregate (e.g. gravel) on the roll to hold it in place. Next, the vehicle advances and unrolls the fabric as the vehicle travels. To hold the fabric in place, the army of workers shovels aggregate, or use spikes to pin the fabric to the sub-grade. Only after the fabric is fully installed, then a second aggregate delivery truck (dump truck), backs to the fabric—to avoid driving on the fabric, which could rip or tear the fragile material—and then dumps the aggregate. Next, a third vehicle (bull-dozer) distributes the piled aggregate on top of the fabric. This is a tedious and time-consuming procedure that must be repeated for the entire length of the road, which could be several dozens of miles.
The state-of-the-art method of installing fabric sheets, according to the “North Carolina Forestry BMP Manual”, Appendix 4 at page 222 of 243 (amended 2006) publication date unknown, includes shaping the roadway and establishing the crown; rolling the fabric, weight the sides and end of the unrolled fabric with shovels full of gravel, or use spikes to pin the fabric down. This method, however, has certain drawbacks. One drawback includes puncturing the fabric with spikes or staples to pin the material: it is undesirable to puncture the fabric as this causes rips and tears in the sheet, and the punctures themselves enable the base layer to intermix with the aggregate layer, which weakens the roadbed. Manpower cost associated with shoveling aggregate on top of the unrolled sheet to weight it down is yet another drawback of this known method.
Certain devices are known to facilitate the laying of paving fabric along a roadbed. For example, U.S. Pat. No. 4,456,399 issued on 26 Jun. 1984 to Conover describes an apparatus for laying paving fabric comprising a core support member of an adjustable length for supporting a roll of paving fabric on a vehicle, a tension applying apparatus secured in the proximity of the fabric roll to remove wrinkles from the web prior to the application to the roadbed, and a broom apparatus for facilitating adherence of the web to the roadbed and a guard for the broom for reducing wrinkling of the fabric.
Yet, there remains a need for improved methods and devices that improve the installation of geotextiles and similar fabric rolls, particularly on temporary road-bed projects. Such tools and methods should minimize worker exposure to injury, reduce manpower required, and reduce expense of installation through time and manpower efficiencies. An improved device and method is needed that enables the unrolling of the fabric roll without requiring spikes to penetrate the fabric to pin the roll in place (as needed, for example, in windy conditions). It would further be desired to have a tool and method that improves efficiencies by combining the rolling of the fabric with the delivery of the aggregate. Such a device, in addition, should be easy to transport to the job site on existing vehicles. Further, such an improved device should be easy to assemble and disassemble by one person.